I do not think Castor is male. I believe they have DSD which is a different biological sex than being male. I do not believe that Castor has male genitalia - that one would have if born male. I do not beleive that Castor has always dentified as male, has always been male and that her childhood experience as reported is untrue and that she was always male and identified as male.
"Male" is a sex. A DSD is a disorder. This is a DSD affecting specifically males (women can have the same hormone deficiency via the same genetic disorder, but it has no noticeable effect on their development).
Yes, Castor has male genitalia, as do all males, just not typically formed, as for all 5-ARD males. And this in turn does not make them "female genitals". They can be mistaken at a cursory glance at birth, but this
Incompletely developed genitals do not stop you being male or female any more than any other development disorder stops you being human. If you're going to argue that Semanya is not male, then by the same logic people with Down's Syndrome are not human. Down's Syndrome is not a different species, and 5-ARD is not a different sex.
Sport does not rely on genitalia, therefore a genital disability has no significant impact. And 5-ARD has little wider impact on overall physical development beyond the genitals. So there's less need for it to be taken into account in sports categorisation than many, many other conditions, such as, I don't know, asthma. There's no reason to treat a male with 5-ARD any differently than any other male. How they "identify" is no more or less relevant than any other male. The reason for a male's "female identification" is irrelevant to the categorisation for fairness.
I do not beleive that Castor has always dentified as male, has always been male and that her childhood experience as reported is untrue and that she was always male and identified as male.
Having read quite a lot over the years, I think the balance of probability is that Semenya was mis-identified as female at birth, but it seems there may not have been any official paperwork for the birth. And it appears that the error was spotted at puberty (as is typical of 5-ARD) or earlier, with Semenya definitely being viewed and treated as male for some period at school - there was testimony from at least one teacher who always thought Semenya was male.
5-ARD males do develop like males, because they're male. The appearance of "female genitalia" at birth is very superficial, and everything else about the body develops as normal for males. And the genitals also develop to be far more male. So a 5-ARD male will not be presumed to be female past puberty, because they will obviously become a man, not a woman.
Then the opportunity came to compete as female via scouts looking for 5-ARD males - so there must logically have been enough knowledge of Semenya's condition somewhere for the scout to find him, even if some only knew Semenya as male.
The authorities knew that as with other athletes the 5-ARD gave them sufficient deniability - either they had real contemporaneous female legal ID based on an actual misidentification, or they could retrospectively create some on the basis that Semenya could/would have plausibly been put down as female at birth. And they could then point at that and deny any later realisation about being male.